Hey all, I'm in a bit of a predicament with the tuning on my truck (early 99). Power is fine and the truck itself runs just fine. However, the issue is the shifting. Long story short, I hate it. I had my transmission beefed up by a local builder about a year ago, but the shifting is still pretty bad. I believe it's due to the early 99 xle4 pcm. With the tuning I'm running now, the torque converter will not lock up in 3rd gear which results in revving the **** out of the motor in 3rd, and if I don't, it bogs down bad in OD. When empty, it's bearable. When towing, it flat out sucks. Therefore, do you guys think a pcm swap to a later, more desirable pcm would help this issue? From what I've read and heard, the later model 7.3 pcm's lock the converter in 3rd which does not result in high revs in 3rd and bogging down in OD. My old tuner locked the converter in 3rd which is why I'm missing the 3rd gear lockup. I switched from this old tuner for other reasons not related to the shifting. The transmission also runs cool. The max trans temp I saw while towing a 4000 pound boat at 70mph was 144*. Also, if a pcm swap is the way to go, where exactly would I get one from? Lastly, a pcm swap is just a simple plug and play for 7.3s right?

 

While it never hurts to have a backup PCM this far from the production date, tuning may be a better option. I have TCLU in 3rd, and when I'm really layin' the meat to the pedal on steep inclines in slow speed zones - the TC stays locked on the downshift to 2. Talk about a good tow tune.

 

Well I was pretty set on getting some gearhead tunes because I've heard of how good their shifting was. However, after looking on gearhead's website and giving them a call, I learned that they do not tune the early 99 pcms. This is mainly why I'm looking to swap pcms. I currently just have canned php tunes, and I called them a while back about tweaking the shifting. They said since my transmission is modified, I'd have to pay $30 per tune because they're custom tunes.

 

I did the PCM swap in my E99. I used a PMT3 PCM, from what I understand each one offers a different shifting platform.

The picture shows what will work in your E99.

 

Here's some additional information. This is the exact PCM I used.

 

Just curious, so you do have a chip now? My E99 is stock PCM and it does lock in third, but not right away when cold. Takes a few miles driving. Don't know what it is waiting for, EOT or TFT to warm up a bit maybe. Purchased the truck from my brother-in-law and he pulled a very big fifth wheel and never complained, go figure.

No, I'm not a transmission expert, still learning differences between the 97 and E99.

 

Yes I have a php hydra with canned tunes currently. I find my self driving in stock mode if I'm putting around town, but if I'm on the highway, I'll put the chip on the 80hp setting for the extra passing power. The stock setting will lock the converter in 3rd sometimes, but still not all the time. I've driven some of my buddy's 7.3s that aren't early 99s, and they are so much more enjoyable to drive. One of them has stock tuning and I still liked that one better than mine. I also have 305/70/16 tires which I think affects the shift points, but I'm not sure.

 

Thanks for digging this up. This is exactly what I'm looking for. I'd hate to buy a pcm and then not have it run right or work at all. I do have a php hydra, so getting new tunes for the new pcm will be a breeze. Also, where did you buy your pcm and did you feel the upgrade was worthwhile?

 

No problem! Yes, it was worth it, truck runs better and shifts better. Finding them is the hard part! I'd look at partouts on CL, put those numbers into Google. ebay etc.